1. Field of the Invention
The present invention relates to a printing method and a printing device usable for fabrics.
2. Description of the Related Art
A known printing device usable for fabrics includes a supply roll around which a lengthy fabric material as a printing medium is wound, a support roll for winding therearound the fabric material fed from the supply roll and guiding the fabric material to a print unit, a print head which is located to be above the fabric material in the print unit and is provided for performing printing on the fabric material, and a winding roll which is rotatable when being driven and is provided for winding therearound the fabric material which has passed the print unit. In such a printing device, each time that one cycle of a print operation is performed, the fabric material is fed toward the winding roll by a prescribed length. The printing device performs printing intermittently.
Japanese Laid-Open Patent Publication No. 2010-052379 discloses a printing device for performing printing intermittently on a lengthy fabric material which is fed from the supply roll. The printing device disclosed in this publication includes a flat plate-like support table (platen) for supporting the printing medium. The printing device uses a print head for performing printing on the printing medium supported by the platen. The printing device also includes a pair of conveyance rollers upstream with respect to the platen in a moving direction of the printing medium. The printing device feeds the printing medium toward the platen while holding the printing medium by the pair of conveyance rollers.
The printing medium, which is conveyed while being supported by the platen, is, for example, damaged by being rubbed with the platen. In the case where the printing medium is a fabric material, the letters or the like printed when the printing medium is on the platen, may be blurred.
Japanese Laid-Open Patent Publication No. 2009-090578 proposes a printing device for solving this problem. In the printing device disclosed in this publication, the lengthy printing medium fed from the supply roll is not supported on the flat plate-like platen for performing printing thereon.
This printing device operates as follows. The lengthy printing medium fed from the supply roll is wound around a support roll. The printing medium is guided by the support roll toward a print unit. The printing device includes a guide roll downstream with respect to the support roll in a moving direction of the printing medium. The print unit is provided between the support roll and the guide roll. In the print unit, a print head is located above the printing medium. The print head is used to perform printing on the printing medium.
The printing medium which has passed the print unit is wound around the guide roll and guided by the guide roll toward a winding roll. Then, the printing medium is wound up around the winding roll.
In this printing device, only the winding roll is actively driven. The winding roll is rotated such that the moving distance of the printing medium per unit time is kept constant. The rotation of the winding roll causes the printing medium to be fed from the supply roll. A prescribed rotation resistance is applied to the supply roll, so that a tensile force of the printing medium is kept constant.
For this printing device, paper is mainly assumed as the printing medium. When this printing device is used to perform printing on a fabric material intermittently, the winding roll is rotated intermittently. Such an intermittent rotation of the winding roll causes the fabric material to be wound intermittently by a prescribed length at a position downstream with respect to the print unit.
However, a fabric material is elastic. Therefore, in the case where the printing medium is a fabric material, the length of the fabric material which is fed in the print unit is not kept constant. As a result, the printing may be performed at a position deviated from the position at which the printing is to be performed. For this reason, the printing device described in Japanese Laid-Open Patent Publication No. 2009-090578 cannot perform printing with high precision when the printing medium is a fabric material.